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RFC-013: Inter-Gandalf Delegation Protocol (IMDP) — 6. Protocol Messages

AIGP Specification › RFC-013: Inter-Gandalf Delegation Protocol (IMDP) › 6. Protocol Messages

← 5. Delegation Flow · Section index · 7. Governance →

6. Protocol Messages

All IMDP messages use HMAC-SHA256 authentication (RFC-010 4) and carry standard AIGP headers.

6.1 CAPABILITY_QUERY

Sent by the originator to discover a delegate’s capabilities before delegating.

GET /imdp/v1/capabilities
Headers:
  X-AIGP-Signature: hmac-sha256={signature}
  X-AIGP-Timestamp: {iso_timestamp}
  X-AIGP-App-Id: {originator_app_id}
  X-IMDP-Request-Id: {delegation_request_id}

Response: Capability manifest (4.2).

The originator MAY query multiple candidates and select the best match.

6.2 DELEGATE

Sent by the originator to request task execution from a delegate.

POST /imdp/v1/delegate
Headers:
  X-AIGP-Signature: hmac-sha256={signature}
  X-AIGP-Timestamp: {iso_timestamp}
  X-AIGP-App-Id: {originator_app_id}
  X-IMDP-Request-Id: {delegation_request_id}
  X-IMDP-Delegation-Depth: {current_depth}
  Content-Type: application/json


Body:
{
  "protocol_version": "1",
  "message_type": "DELEGATE",
  "delegation_id": "del-1714900000000-abc",
  "originator": "identity-service",
  "delegate": "analytics-service",
  "capability_id": "policy_conversion",
  "delegation_depth": 1,
  "max_execution_seconds": 120,
  "context": {
    "assembled_by": "identity-service",
    "acp_sources": [
      {
        "provider": "identity-service",
        "context_type": "source_policies",
        "schema_version": "1.0"
      }
    ],
    "payload": { ... }
  },
  "callback_url": "https://scim-prj.your-identity-service.com/imdp/v1/result",
  "timeout_seconds": 120
}

Key fields:

Field Description
delegation_id Unique identifier for this delegation chain
originator The Gandalf that owns the user interaction
delegate The Gandalf being asked to execute
capability_id The specific capability being invoked
delegation_depth Current depth (1 = first delegation, 2 = sub-delegation)
context ACP-assembled context payload
callback_url Where to send the result (async pattern)
timeout_seconds Max time before the originator considers the delegation failed

6.3 DELEGATE_RESULT

Sent by the delegate back to the originator upon completion.

POST {callback_url}
Headers:
  X-AIGP-Signature: hmac-sha256={signature}
  X-AIGP-Timestamp: {iso_timestamp}
  X-AIGP-App-Id: {delegate_app_id}
  X-IMDP-Request-Id: {delegation_request_id}
  Content-Type: application/json


Body:
{
  "protocol_version": "1",
  "message_type": "DELEGATE_RESULT",
  "delegation_id": "del-1714900000000-abc",
  "delegate": "analytics-service",
  "originator": "identity-service",
  "capability_id": "policy_conversion",
  "status": "SUCCESS",
  "duration_ms": 45200,
  "result": {
    "context_type": "conversion_state",
    "schema_version": "1.0",
    "data": {
      "conversion_id": "conv-20260504-001",
      "total_policies": 47,
      "converted": 42,
      "gaps": 3,
      "manual_review": 2,
      "confidence_score": 0.89
    }
  },
  "sub_delegations": [],
  "tokens": {
    "input_tokens": 12400,
    "output_tokens": 3200,
    "total_tokens": 15600
  }
}

Status values:

Status Meaning
SUCCESS Task completed successfully
PARTIAL Task partially completed result contains what was achieved
FAILED Task failed error field contains details
TIMEOUT Delegate did not complete within timeout_seconds
REJECTED Delegate rejected the delegation (capability mismatch, overloaded)

Error response:

{
  "protocol_version": "1",
  "message_type": "DELEGATE_RESULT",
  "delegation_id": "del-1714900000000-abc",
  "status": "FAILED",
  "error": {
    "code": "CAPABILITY_UNAVAILABLE",
    "message": "policy_conversion is temporarily unavailable due to upstream dependency",
    "retryable": true,
    "retry_after_seconds": 60
  }
}

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